1. Field of the Invention
The present invention relates to a lock and a two step method to open the lock, and more particularly to a two step method to open a lock where key serrations access lock pins from the back of the lock.
2. Description of Related Art
Locks secure doors, drawers, suitcases, etc. so no one can open them without keys. A conventional lock in accordance with the prior art comprises a cylinder, a cylinder plug, a latch and multiple locking pins. The cylinder has multiple outer pin holes. The cylinder plug is mounted rotatably in the cylinder and has multiple inner pin holes and a keyhole. The inner pin holes are aligned respectively with the outer pin holes. The keyhole is defined in the cylinder plug and communicates with the inner pin holes. The locking pins are spring-loaded pins and are mounted respectively in the outer pin holes. The locking pins extend into and are partially held in the aligned inner pin holes so that the cylinder plug cannot rotate relative to the cylinder. The latch is attached to and rotated by the cylinder plug.
A key having a blade with serrations corresponding to the locking pins is required to open the lock. The key is inserted into the keyhole in the cylinder plug to push the locking pins in the inner pin holes out of the inner pin holes. When the locking pins are flush with the exterior surface of the cylinder plug, the cylinder plug can be rotated relative to the cylinder so that the lock can be opened.
However, a thin and long pick inserted into the lock through the keyhole can push the locking pins out of the pin holes in the cylinder plug to open the lock. Consequently, locks should have an enhanced configuration to prevent the lock from being easy to pick. The aforesaid conventional lock has the following shortcomings.
First, the convention lock is easy to pick. A thin and long pick may be inserted into the keyhole to push the locking pins and open the lock without a key. Therefore, the conventional lock cannot prevent the door, the drawer, the suitcase, etc. from being opened.
Second, foreign objects are often inserted into the lock through the keyhole to disable the lock. The foreign objects such as toothpicks, chewing gun or pieces of paper will be held in the keyhole so that the key for the lock is impossible to access the locking pins. The key only pushes the foreign objects further into the keyhole, which keeps the lock from being operated normally.
To overcome the shortcomings, the present invention provides an improved lock and a method to open the lock to mitigate or obviate the problems with conventional locks.